Editor's Note: Growing requirements for increased availability of IoT devices coincide with the emergence of cellular technologies well suited for the IoT. For developers, the need has never been more acute for more detailed information about cellular technologies and their application to the IoT. Excerpted from the book, Cellular Internet of Things, this series introduces key concepts and technologies in this arena.

In an earlier series, the authors described the evolving landscape for cellular, its role in the IoT, and technologies for massive machine-type communications (mMTC) and ultra reliable low latency communications (URLLC).

The choice of a CIoT solution is a decision that needs to be taken by different market players. On one hand, it is the mobile network operator that has to decide which CIoT technology to add to its existing network. On the other hand, it is the IoT device manufacturer and service provider, which select for which IoT connectivity options they develop their IoT service. It can be expected that different options of solutions will coexist.

9.3.2.1 The Mobile Network Operator’s Perspective

For a mobile network operator, the decision about which CIoT technology to deploy and operate has multiple facets. There are in particular two sides that need to be considered:

Long-term mobile network strategy and existing assets,

IoT market segment strategy.

A typical mobile network operator has one or more cellular networks deployed. Increasingly, different radio technologies are provided via a single multiradio technology network. For example, the same base station can be used for GSM, UMTS/HSPA, or LTE transmission. But there are also deployments where the networks for 2G, 3G, and 4G are rather independent in their deployment and operation.

In addition, a mobile network operator has a spectrum license from typically a national regulator, which gives rights to operate a network in the assigned spectrum. Spectrum licenses are typical long-lasting, like e.g., 20 years; this is motivated by providing network operators with an economic safety. A return on investment for an extremely high network installation cost of a new technology can be planned over a long period. On expiry of a spectrum license, a spectrum licensing contest, like a spectrum auction, is initiated by the regulator for providing a new spectrum license. In general, any network build-out roadmap by an operator is a long-term decision and needs to consider at least the following elements:

How long are the existing spectrum licenses valid, what technologies are allowed to be operated in the spectrum, and when is a new spectrum reallocation process planned by the regulator?

What is the status of the network build-out for different radio technologies, in particular GSM and LTE, and what is the operator’s market share?

What is the network build-out of competing operators and what is their market share?

What is the strategic intent of an operator concerning IoT?

What services are planned to be provided, and on what roles does the operator intend to address the IoT market (e.g., as connectivity provider or also as service provider/enabler)?

What is the market maturity for IoT services?

What IoT segment would the operator like to address?

It shall be noted that the above questions are raised from a perspective of the operation of an operator network in a specific country. However, several operators are active in multiple countries and even on multiple continents. Even if the decision is largely made per country, an operator may want to harmonize decisions over multiple regions in which it operates networks.

When looking at the CIoT technology options, the following characteristics can be identified, which will influence an operator’s decision.

As a baseline, we assume that there is a very large incentive by an operator to reuse existing mobile network infrastructure for deploying any of the CIoT technologies. Naturally, EC-GSM-IoT can be easily deployed based on a GSM infrastructure and by using GSM spectrum. The GSM network resources and the GSM spectrum would be shared between GSM usage and EC-GSM-IoT usage. LTE-M and NB-IoT can be deployed based on an LTE infrastructure and by using the LTE spectrum; LTE network and spectrum resources would be shared between LTE, LTE-M, and NB-IoT usage. In most network configurations, it can be expected that the deployment of EC-GSM-IoT, LTE-M, and NB-IoT can be realized as a software update to the deployed GSM or LTE networks. This implies that the introduction of the CIoT into the market can be realized by operators rather quickly and at a low total cost of ownership.

For IoT services it is expected that many services expect a long service lifetime of, e.g., a decade. This expectation should be addressed with a CIoT network. As a result, the decision of the CIoT technology is also coupled to the operator’s long-term strategy for mobile networks focusing on telephony and mobile broadband services. If an operator intends to transition GSM deployments to, e.g., LTE or 5G in the coming future, an introduction of EC-GSM-IoT seems a questionable choice, as any long-term EC-GSM- IoT users would require to maintain the GSM infrastructure operational for a long time.

GSM is today still the cellular network technology, which covers the largest part of the globe. According to Reference [55] in 2016 around 90% of the world population was within coverage of a GSM network, and this is expected to increase to w95% by 2022. In contrast, in 2016 only around 40% of the population were within the coverage of an LTE network, which is expected to increase to more than 80% by 2022. However, there are very large regional variations in the spread of cellular technologies. To give some example from Reference [55], in the Middle East and in Africa only 5% of mobile subscriptions in 2016 were LTE subscriptions (which also enable to use WCDMA/HSPA and GSM); this number is expected to increase to around 30% by 2022. Approximately 20% of the subscriptions are GSM-only and a majority of subscriptions is for WCDMA/HSPA (which also enables to use GSM but not LTE). In regions like Middle East and Africa, GSM is predicted to continue being an important technology for many years to come, even if in other regions the mid- and long-term role of GSM is less certain. Looking at North America, already in 2016 65% of mobile subscriptions were LTE subscriptions. For 2022 very few non-LTE-capable [see Note 1] subscriptions are foreseen. Such differences will result in different preferences of CIoT solutions for different operators in different regions. [Note 1: As LTE-capable subscription in 2022 we count here the predicted LTE subscriptions as well as 5G subscriptions, which are assumed to be fully compatible for operation in LTE networks.]